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Import risk analysis: Llamas (Lama glama) and alpacas (Vicugna ...

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14. Foot <strong>and</strong> mouth disease virus<br />

14.1. HAZARD IDENTIFICATION<br />

14.1.1. Aetiological agent<br />

Family: Picornaviridae; Genus: Aphthovirus; Species: Foot <strong>and</strong> mouth disease virus<br />

(FMDV). There are seven serotypes of the virus: O, A, C, SAT 1, SAT 2, SAT 3, <strong>and</strong> Asia<br />

1 (Stanway et al 2005).<br />

14.1.2. OIE list<br />

Listed as a disease of multiple species.<br />

14.1.3. New Zeal<strong>and</strong> status<br />

Listed on the Unwanted Organisms Register as an exotic notifiable disease.<br />

14.1.4. Epidemiology<br />

Extensive reviews on foot <strong>and</strong> mouth disease are available (Sanson 1994; Thomson &<br />

Bastos 2004) <strong>and</strong> much of the information given below is taken from these. The disease<br />

has been eradicated from, or has not occurred in, countries relevant to this <strong>risk</strong> <strong>analysis</strong><br />

except for South American countries. It can infect all cloven hoofed animals <strong>and</strong> is<br />

considered to be the most contagious <strong>and</strong> economically devastating animal disease. The<br />

outbreaks of the disease in Britain in 2001 (Thompson et al 2002) <strong>and</strong> in Taiwan in 1997<br />

(Yang et al 1999) cost those countries billions of dollars.<br />

Infected animals excrete the virus in saliva, faeces, urine, milk, semen, ocular <strong>and</strong> nasal<br />

discharges (Sanson 1994; Thomson & Bastos 2004), <strong>and</strong> virus is also discharged in aerosol<br />

in expired air. The incubation period is usually 2-14 days (Sanson 1994). Viraemia usually<br />

continues from 1 day before until 11 days after signs of disease first appear. Transmission<br />

can be from direct contact, contact with infected fomites, ingestion of infected animal<br />

products or from inhaling aerosolized virus (Sanson 1994; Thomson & Bastos 2004).<br />

Long- term carriers excrete small amounts of virus from the pharynx. Cattle may excrete<br />

virus in this way for up to 3 years. However, the amount of virus excreted by persistent<br />

carriers is low <strong>and</strong> the ability of persistently infected cattle to spread the disease is<br />

controversial (Thomson & Bastos 2004).<br />

Camelids are susceptible to foot <strong>and</strong> mouth disease. However, several investigations<br />

indicate that they are much more resistant to the infection than cattle, carry the virus for<br />

only short periods <strong>and</strong> are not highly infectious (Fowler 1992; David et al 1994; Viera et al<br />

1995; Wernery & Kaaden 2002; Wernery & Kaaden 2004). According to Fowler (1992)<br />

Mancini infected South American camelids experimentally <strong>and</strong> was able to transmit the<br />

disease by injection into the epidermis of the tongue, intramuscular <strong>and</strong> intravenous<br />

injection <strong>and</strong> by cohabitation. The first lesions developed 48-72 hours after infection.<br />

Some llamas infected intramuscularly or intravenously died but transmission by<br />

cohabitation was not always successful. It was concluded that camelids are less susceptible<br />

than cattle <strong>and</strong> sheep. In another study only two out of 10 llamas developed slight lesions<br />

when placed in contact with infected pigs <strong>and</strong> infected llamas carried the virus in the<br />

oesophageal-pharyngeal region for only short periods compared to cattle (David et al<br />

46 ● <strong>Import</strong> <strong>risk</strong> <strong>analysis</strong>: <strong>Llamas</strong> <strong>and</strong> <strong>alpacas</strong> from specified countries MAF Biosecurity New Zeal<strong>and</strong>

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